This application is based on U.S. Provisional Patent Application Ser. No. 60/076,962, Pulmonary Dosing System and Method, Michael J. Brooker, et al., filed Mar. 5, 1998.
The invention relates to a pulmonary dosing system and method for supplying to a patient a predetermined amount of respirable therapeutically active material entrained in filtered atmospheric air, and more particularly to such a system and method which is compact, self-contained, and capable of supplying any respirable therapeutically active material including toxic drugs such as chemotherapy drugs.
Prior art workers have devised a number of different systems for delivering respirable therapeutically active material intended for use in conjunction with mechanical respirators, ventilators, or breathing machines. The present invention, on the other hand, is directed to a pulmonary dosing system for supplying a patient with a predetermined amount of respirable therapeutically active material, the patient being capable of normal inhalation and exhalation, on his own.
The pulmonary dosing system of the present invention is able to contain the therapeutically active material or drug to the extent that it can safely administer toxic drugs such as chemotherapy drugs.
The respirable therapeutically active material is entrained in pulses of air synchronized with the patient""s exhalations. Except for the inhalation tube, the exhalation tube and the patient interface connected thereto, the remainder of the inhalation and exhalation portions of the system including the delivery apparatus for the therapeutically active material are located in a sealed containment case. The containment case is subjected to a mild vacuum from a vacuum source including a filter to further assure containment of the therapeutically active material, if necessary. The system is provided with a control unit containing a compressor and valve to provide pulsed air, a vacuum pump to provide the mild vacuum within the containment case, and a computer with inputs from various sensor devices together with a number of interfaces with the operator and with the patient.
One of the more advantageous features of the drug delivery or pulmonary dosing system is its efficiency in delivering drugs. This may be particularly important with respect to the time spent by the patient and the support staff for each treatment and also with respect to reducing the expense of extremely costly drugs. The efficiency refers not only to the efficiency of delivering drug to the patient (not lost in the delivery system), but also to the efficiency of getting the delivered drug to penetrate deep into the lung of the patient to provide the needed therapy. The present invention reduces the amount of aerosolized drug that may be deposited in the mouth, the upper airway, or the nasal cavity.
One of the novel features which adds to this efficiency is the combination of the nebulizer (or other aerosol-producing device), the plenum, an air supply and the control system which are combined to provide a metered dose of drug and air to the patient at the designated time for inhalation. In one efficient operation, the aerosol-producing device is controlled to deliver a selected volume of drug aerosol to the plenum prior to the inhalation phase of the patient. As described herein, this is advantageously performed by sensing the exhalation phase of the patient and then providing a pulse of air to the nebulizer which results in a metered volume of aerosolized drug in the plenum.
It is an object of the present invention to provide a pulmonary dosing system for supplying to a patient capable of normal breathing a predetermined amount of respirable therapeutically active material.
It is an object of the present invention to provide a dosing system connectable by a power cord to a source of electricity of standard hospital voltage and which is otherwise completely self-contained.
It is an object of the present invention to provide a delivery system wherein that portion of the system between the inhalation and exhalation tubes and their interface with the patient and a control unit are maintained in a containment case to preclude escape or leakage of the respirable therapeutically active material being dispensed to the patient.
It is an object of the present invention to provide a control unit containing a compressor together with a pulsing valve, a vacuum pump to maintain the containment case under a mild vacuum, a computer having interfaces with both the operator and the patient, the operator interfaces enabling the operator to set the number of exhalations between air pulses, the duration of each air pulse, and the amount of the respirable therapeutically active material to be dispensed.
It is an object of the present invention to provide a system capable of supplying at least one non-toxic drug to the patient.
It is an object of the present invention to provide a system capable of dispensing at least one toxic drug to the patient.
It is an object of the present invention to provide an interface between the patient and the inhalation and exhalation tubes in the form of a mouthpiece constituting a part of a mask, the mask further having an outlet leading to a filter in case the patient coughs.
According to the invention there is provided a pulmonary dosing system and method for supplying to a patient a predetermined amount of respirable therapeutically active material. The system comprises a patient interface to introduce the material into the patient""s lungs. This interface may constitute a mouth tube, a mask and mouth tube combination, a trachea tube, a nasal tube, or the like. The patient interface is connected to a flexible inhalation tube and a flexible exhalation tube. The exhalation tube is connected to a filter, the outlet of which is connected to atmosphere. The inhalation tube is connected to an apparatus for providing pulsed amounts of the material entrained in filtered atmospheric air. Preferably, the apparatus comprises a nebulizer having an inlet for pulsed air, a plenum chamber and a connection, provided with a filter, to atmospheric air.
A control system is provided to operate the pulmonary dosing system in accordance with operator inputs selecting the number of patient exhales between pulses, the pulse length, and the amount of material to be dispensed to the patient. The exhaust filter and the apparatus for providing pulsed amounts of the therapeutically active material may be enclosed in a containment case. The dosing system is capable of supplying at least one non-toxic drug, or at least one toxic drug to the patient.